To find an ideal adsorbent for carbon dioxide capture, a new polyethyleneimine modified silica gel material was synthesized with a simple procedure. Three silica gel materials with various particle sizes (15, 25 and 40-63 µm) were prepared and functionalized with polyethyleneimine. The carbon dioxide adsorption amounts of modified silica gel and non-modified silica gel were calculated using a mass balance equation at three different temperatures (298.15, 308.15 and 318.15 K), respectively, and the influence of gas pressure and particle size on adsorption was discussed. Experimental data showed that the carbon dioxide adsorption capacity of modified silica gel was better than non-modified silica gel, and the adsorption capacity gradually decreased with increasing particle size. The smaller particle size (15 µm) PEI modified silica gel had the largest adsorption capacity, at 298.15 K, and the adsorption amounts of various particle sizes of PEI-silica better fit the Langmuir isotherm model.

: The adsorption kinetics of cephalosporin-c (CPC) on non-ionic polymeric macropore Amberlite XAD-16 resin were investigated in a well-stirred tank. The 'half-time' and non-linear methods were used to derive the intraparticle diþ usivities from the experimentally determined adsorption uptake curves. It was found that both pore and solid surface diþ usion processes made signiücant contributions, in parallel, to the intraparticle mass transfer. It was also found that the CPC concentration had an eþ ect on the eþ ective pore and surface diþ usivities. The results are relevant to the mathematical modelling of adsorption processes.

To optimize the performance of an adsorption bed, layered beds of activated carbon and zeolite 5A are used for multicomponent gas separation (H 2 : 72.2%, CO 2 : 21.6%, CO: 2.03%, CH 4 : 4.17%). The adsorption dynamic characteristics were studied experimentally and theoretically using layered beds of activated carbon and zeolite 5A at 8 atm adsorption pressure and 16.67 L/min feed rate. Non-isothermal and non-adiabatic models, based on a linear driving force model and Dual-Site Langmuir adsorption isotherm model, were used. As the carbon ratio increased, the average velocity of CH 4 wavefront became slow, and wavefronts of CO and CO 2 propagated quickly on average.

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